﻿     var code ; //在全局 定义验证码   
     function createCode()   
     {    
       code = "";   
       var codeLength = 3;//验证码的长度   
       var checkCode = document.getElementById("code");   
       var selectChar = new Array(0,1,2,3,4,5,6,7,8,9,'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z');//所有候选组成验证码的字符，当然也可以用中文的   
           
       for(var i=0;i<codeLength;i++)   
       {   
         
           
       var charIndex = Math.floor(Math.random()*36);   
       code +=selectChar[charIndex];   
          
          
       }   
       //alert(code);   
       if(checkCode)   
       {   
         checkCode.className="code";   
         checkCode.value = code;   
         //checkCode.innerHTML= "sdlakfjalksjf";  
       }   
          
     }   
        
function validate()   
     {   
       var inputCode = document.getElementById("validate").value;   
       if(inputCode.length <=0)   
       {   
           document.getElementById("alert").innerHTML="<font color='red'>请输入验证码</font>";
           document.getElementById("validate").value="";
       }   
       else if(inputCode.toLowerCase() != code.toLowerCase() )   
       {   
          document.getElementById("alert").innerHTML="<font color='red'>验证码错误</font>";
           document.getElementById("validate").value="";
          createCode();//刷新验证码   
       }   
       else
       {
          document.getElementById("alert").innerHTML="<font color='red'>√</font>";
        }
}   
